Chinese authorities arrested a knife-wielding man accused of stabbing to death seven children and wounding 12 others on Friday in northwest China, The Guardian reported.

What's the story?

The 28-year-old suspect allegedly murdered five boys and two girls who were on their way home from Mizhi County Number Three secondary school in Shaanxi province, according to Mizhi County’s Public Security Bureau.

The attack occurred at about 3:10 p.m. outside the school as the children were leaving for the day.

Emergency responders transported the wounded — nine girls and three boys — to a hospital. Their conditions were not immediately known.

It's being called one of the deadliest massacres in China in recent years.

Authorities have not verified the ages of the victims, but middle school children in China are typically between the ages of 12 and 15, according to reports.

The People's Daily, a China newspaper, tweeted photos from the scene that showed police taking a man into custody.

What was the killer's motive?

The suspect told police he was a former student at the school who was bullied in the third grade.

He said decided to take a dagger and kill people on Friday because he hated his classmates.